Broken-web control for wrapping machines



June 26, 1934.

F. MERTIS BROKEN WEB CONTROL FOR WRAPPING MACHINES Filed March 28, 1933 umen ,4 I ATTORNEY Patented June 26, 1934 UNITED STATES PATENT OFFICE BROKEN-WEB CONTROL FOR WRAPPING MACHINES Application March 28, 1933, Serial No. 663,235

3 Claims.

This invention relates to motor cut-out devices for wrapping machines, its main object being to automatically stop the driving motor of a machine employing wrapping material in the form of one or more continuous webs, fed from reels in the machine, in case of breakage or tearing of one or more of these webs during the operation of the machine.

In the present invention, this object is achieved by the use of Mercoid switches bearing on the wrapping material as it is being advanced to be wrapped around the article.

In case of breakage or tears in the web of the wrapping material, the Mercoid switch will lose its support and drop when the break or tear in the web reaches the switch, thereby permitting the latter to tilt sufliciently to break the electrical circuit, which will result in the stoppage of the driving motor. With this and other objects not specifically mentioned in view, the invention consists in certain constructions and combinations hereinafter fully described and then specifically set forth in the appended claims.

In the accompanying drawing which forms a part of this specification and in which like characters of reference indicate the same or like parts,

Fig. 1 is aportion of the side elevation, with portion of frame shown broken away, of a wrapping machine equipped with this improved broken-web control device;

Fig. 2 is a top view of the control device, as mounted in position on the web;

Fig. 3 is a side elevation of the control device, showing the same in closed circuit position, when the web is continuous; and

Fig. 4 is a side elevation of the control device showing the same in the open circuit position, when there is a break in the web.

In carrying the invention into effect there is provided a pivoted lifter table, means for oscillating said table about its pivot to intermittently raise it from a downwardly inclined to a horizontal position, a runway arranged to guide loaves of bread into position to be delivered to said table while the latter is in the inclined position, devices for guiding a web of wrapping material between said runway and table, mechanism for pushing a loaf from said runway onto said table while the latter is in inclined position to partially enfold the loaf in the web, a motor driving said means and mechanism, and an electric circuit for supplying current to said motor. In the best forms of construction contemplated the electric circuitincludes a pivoted Mercoid switch resting on said web and thereby maintained in closed circuit position, whereby the Mercoid switch will drop into open circuit position and stop the motor when it encounters a break or tear in the web. In the preferred form of construction the electric circuit includes a supply circuit connected to said motor, a step-down transformer connected to said supply circuit, a relay connected to said transformer and switch, and a make-and-break solenoid contact in the supply circuit controlled by the relay to break the supply circuit when the Mercoid switch drops into open circuit position- These various means and parts may be widely varied in construction within the scope of the claims for the particular device selected to illustrate the invention is but one of many possible concrete embodiments of the same. The invention, therefore, is not to be restricted to the specific construction shown and'described.

Referring to the drawing, the side frames 10 of the wrapping machine, which is of the type shown in the patent to H. Y. Armstrong, No. 1,626,379, granted April 26, 1927, carry brackets 11- which support cross-shaft 12 on which the reel R of wrapping material is mounted.

The wrapping web W is threaded over rollers 13, 14, 15 and 16, then passed over support plate 17 and finally over roller 18 from which it hangs over the feed runway 20 where article A is delivered to be wrapped.

As the article A is advanced from runway 20 to a lifter table 21, when the latter is in its down position 21', shown in dotted lines, the downhanging wrapper web W is carried along by the article A, thereby partly folding the web W ried by a shaft 27 driven by a chain 28 from a motor 29.

As article A enters into position on table 21', side tuckers 30 then in the down position 30', are caused to close upon the article, thereby tucking the forward'side laps of the wrapper W and holding them in position while the table 21 ascends to its up-position 21. In approaching the latter position, the laps of the top fold encounter stationary folding plates 31, causing the top flaps of the wrapper W to be folded against the article, forming a partly finished package P.

The swinging table 21 is operated by a cam 32 mounted on the drive shaft 2'7 and actuating a bell-crank lever 33 connected to the platform 21 by a rod 34.

While the lifter table 21 dwells in its upper position. a cam-actuated paper pull-off rod, not shown, swings down and unwinds from reel R a sufiicient length of wrapping material for the next package. Upon completion of the downward swing of the pull-off rod, a knife, not shown, cuts the web to suitable length for completely encircling the article enfolded in the leading end of the web.

In order to provide against a jam or an imperfectly wrapped package in case of tear or breakage of the wrapping web W, Mercoid switches of well known construction for controlling the driving motor 29 are suspended over the web with their supporting fingers placed near the edge of the web.

- The Mercoid" switches are free to swing around their pivot 36 which is rigidly connected to adjusting blocks 37 which are threaded to engage adjusting screw 38. Rod 39 supports adjusting block in one direction and bar 40 supports it in the opposite direction, thus keeping it from rotating as the adjusting screw is turned to adjust the position of the Mercoid switches with respect to the edges of the web.

when wrapping web Wis running through in perfect condition, finger 35 rests on its top surface, thus keeping the Mercoid switch in closed circuit position but if a tear or break in the web occurs, finger 35 will drop at the point of damage and thus throw the Mercoid" switch into open circuit position.

With the Mercoid switches in closed circuit.

position, the current flows by a wire to one terminal of a relay 51, fed by the low-volt side of a step-down transformer 52, the other terminal of which completes the circuit through the Mercoid switch by wire 53.

The transformer is fed through wires 54 from the lines 55, which in the diagram are shown as part of a single-phase A. C. supply circuit passing through the motor starting switch 56 from which the motor 29 of the machine is supplied with current through the wires 57 alsoforming a part of the supply circuit.

The secondary circuit 58 of the relay 51, which includes a contact held in closed position by the relay when the latter is energized, receives current from the lines and controls a make-and-break solenoid contact 59 for the flow of the motorcurrent in circuit 57.

When, during the operation'of the machine, with the starting switch 56 closed, a tear or break in the web occurs, the finger 35, on which the "Mercoid switch is mounted, will drop into the open space at the tear causing a break in the circuit at the Mercoid switch. The break in the circuit at the Mercoid switch will interrupt the flow of current through wires 50 and 53 into relay 51, thereby deenergizing the latter and releasing the contact in its secondary circuit 58 to cause the make-and-break contact 59 to become deenergized, thus opening said contact and discontinuing the flow of current in wire 57, thereby stopping the motor 29.

For convenience of the operator a manually opclined to a horizontal position, a runway arranged to guide loaves of bread into position to be delivered to said table while the latter is in the inclined position, devices for guiding a web of wrapping material between said runway and table, mechanism for pushing a loaf from said runway onto said table while the latter is in inclined position to partially enfold the loaf in the web, a motor driving said means and mechanism,'and an electric circuit for supplying current to said motor, said circuit including a pivoted Mercoid" switch resting on said web and thereby maintained in closed circuit position, whereby said switch will drop into open circuit position and stop said motor when it encounters a break or tear in the web.

2. The combination with a pivoted lifter table,

of means for oscillating said table about its pivot to intermittently raise it from a downwardly inclined to a horizontalposition, a runway arranged to guide loaves of bread into position to be delivered to said table. while the latter is in the inclined position, devices for guiding a web of wrap- 1 ping material between said runway and table. mechanism for pushing a loaf from said runway onto said table while the latter is in inclined position to partially enfold the loaf in the web, a A

motor driving said means and mechanism, and an electric circuit for supplying current to said motor, said circuit including a pivoted Mercoid" switch resting on said web and thereby maintained in closed circuit position, whereby said switch will drop into open circuit position and stop said motor when it encounters a break or tear in the web, said electric circuit including a supply circuit connected to said motor, a stepdown transformer connected to said supply circuit, a relay connected to said transformer and switch and a make-and-break solenoid contact in said supply circuit controlled by said relay to break said supply circuit when said switch drops into open circuit position.

3. The combination with devices for guiding a web of wrapping material, of a driving motor, and an electric circuit for supplying current to said motor, said circuit including a pivoted Mercoid" switch bearing against said web, and

adapted to move into open circuit position to break saidcircuit and stop said motor when it encounters a break or tear in the web, a supply circuit connected to said motor, a step-down transformer connected to said supply circuit, a

relay connected to said transformer and switch. 

